Published: Dec 28, 2010 7:02 PM EST
Updated: Dec 28, 2010 4:17 PM EST

JOS, Nigeria (AP) - A radical Muslim sect has claimed responsibility for the Christmas Eve bombings and church attacks in Nigeria that killed at least 38 people, and the group threatened new attacks to avenge local violence against Muslims.

Religious fighting has left more than 500 people dead this year in the deeply divided region where Jos is located. Authorities had already blamed the Boko Haram group for some of the deaths Friday, but the online statement attributed to the group was the first solid connection between the violence in two cities.

"Therefore we will continue with our attacks on disbelievers and their allies and all those who help them," the statement said.

It was not immediately possible to contact members of the sect, which had not previously used the website where the statement appeared. The head of national police Yemi Ajayi also said Tuesday that authorities were still investigating.

Two bombs went off near a large market in Jos where people were doing last-minute Christmas shopping Friday. A third hit a mainly Christian area of Jos, while the fourth was near a road that leads to the city's main mosque.

Officials initially said at least 32 died from the blasts, and police have not updated that figure publicly.

An official with the National Emergency Management Agency told journalists that he had counted 80 deaths, but the regional NEMA coordinator said only three hospitals were visited. It was not verified whether the patients counted were in fact blast victims, said the regional NEMA coordinator, Alhassan Aliyu Danjuma.

That same day, two churches were attacked in the northern city of Maiduguri about 320 miles (520 kilometers) away, killing at least six people. Nigerian authorities blamed Boko Haram, and said a Baptist pastor and two choir members preparing for a late-night carol service were among the victims.

The radical Muslim sect is also known by a much longer Arabic name, which means "the organization of followers of the teachings of Prophet Muhammad and champions of Islam and holy wars."

It was thought to be vanquished in 2009 after Nigeria's military crushed its mosque into concrete shards, and its leader was arrested and died in police custody.

But now, a year later, Maiduguri and surrounding villages again live in fear of the group, whose members have assassinated police and local leaders and engineered a massive prison break, officials say. Western diplomats worry that the sect is catching the attention of al-Qaida's North Africa branch.

While religious violence in the central city of Jos and neighboring towns and villages has claimed more than 500 lives this year, the fighting has not typically been linked to Boko Haram.

Nigeria, a country of 150 million people, is almost evenly split between Muslims in the north and the predominantly Christian south. Jos is in the nation's "middle belt," where dozens of ethnic groups vie for control of fertile lands.

The Jos violence, though fractured across religious lines, often has more to do with local politics, economics and rights to grazing lands. The government of Plateau state, where Jos is the capital, is controlled by Christian politicians who have blocked Muslims from being legally recognized as citizens. That has locked many out of prized government jobs in a region where the tourism industry and tin mining have collapsed in the last decades.

--- Associated Press Writer Njadvara Musa contributed from Maiduguri, Nigeria.

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